A jobless father apologised to his six-year-old daughter before stabbing her mother to death in the street, a court heard.

Moments earlier Mark Morris, 39, was told by his 33-year-old ex-girlfriend, Emma Day, who was also the mother of his child, that if he could afford alcohol he could pay child support.

Incensed that she would not a be a 'good girl' and drop demands he paid for his own child, he ran after her as she walked away and plunged a large kitchen knife into her back in Thornton Heath, south London, authorities say.

Morris murdered Miss Day nine days after she made another application to the Child Maintenance Service, the court heard.

Mark Morris, 39, was told by his ex-girlfriend, Emma Day, who was also the mother of his child, that if he could afford alcohol he could pay child support moments before he killed her in south London in May, the court heard

He was told the payments - £1,277 a year, or £24.56 a week - would be smaller than an earlier estimate.

Sarah Whitehouse QC, prosecuting, told the Old Bailey: 'Although the amount he was being asked to pay was relatively modest, his earnings were also relatively modest.'

Miss Day said she was 'struggling' and had two children to feed, but he accused her of doing it for 'revenge', adding: 'You leave me with no choice.'

On the day of the attack, May 25, 2017, Morris text his mother saying: 'I'm saying goodbye to all of you. If I'm still alive please don't visit me. Just tell everyone I'm sorry but I had to do this.'

At 5.45pm the day of the attack, Morris bought a can of beer and sat down on a wall near Miss Day's home in West Norwood, south London.

A few minutes later, she walked past with her 13-year-old son, from another relationship, but they did not say anything.

At 6pm, Morris text her saying, 'Ok just so I understand this, your (sic) gonna go through with cms?'

But Miss Day did not reply but asked her friend Sallie Clarke if she could accompany her home, as Morris was making her nervous as he was so 'unpredictable'.

Morris bought another beer and hid in the road, before emerging when the two women and children walked past at 6.30pm.

Ms Whitehouse said: 'He seemed sweaty, dirty and under the influence of alcohol. He approached the group, and said to his daughter, 'I'm really sorry.' The daughter backed away.

'Mr Morris then started to beg Emma about the child support payments. Miss Day insisted that the arrangements were fair and he had a duty to contribute.

'Mr Morris became verbally abusive and complained that he would be left homeless. He said that he was in debt and owed over £6,000.'

Concerned about his 'agitated and volatile' state, Miss Clarke sent the children towards their home.

Morris murdered Miss Day nine days after she made another application to the Child Maintenance Service, the court heard. Pictured above, the crime scene in Thornton Heath, south London

Meanwhile Morris sat on a wall and rolled a cigarette, telling Miss Day she had to be a 'good girl' and 'do what she was told', and that he had drunk 'four cans'.

Ms Whitehouse said: 'Miss Day responded that if he had money to buy alcohol he equally had money to pay child support.'

She walked away with Miss Clarke, who saw Morris run towards Miss Day with a long kitchen knife and plunge the blade into her back in one motion, the court heard.

The prosecutor said: 'Emma called out, 'what are you doing?' They were to be her last words.

'Despite a struggle between Miss Clarke and Mr Morris, he was able to lunge at Emma Day, slashing her neck in the process.

'Mr Morris then ran off down the hill, but not before he had discarded the knife.'

The victim had two stab wounds to her back penetrating her lung, and she was declared dead at the scene at 7.41pm.

Morris also called 999, claiming he was not there but was told she was injured.

At 7.10pm, he called his mother saying, 'I've done it, the thing we spoke about. I've stabbed her'.

Body cam footage showed Morris being arrested in his bed the next day, May 26.

Morris told police: 'I knew what I had done. I could not stop myself.'

He later said he had made regular contributions to Miss Day, but had lost his job and got into debt so stopped before Christmas 2016.

Morris, a former Asda worker, admitted murder and having an offensive weapon last week.

He pleaded guilty to manslaughter at an earlier hearing, but prosecutors did not accept the plea.

The Old Bailey heard on Thursday how Miss Day and Morris had been locked in a bitter dispute over child maintenance payments.

They had been in a relationship from 2008 until they split in March 2016.

In April 2016, Miss Day, who worked as a receptionist on the neuroscience ward at King's College Hospital, reported to police she was being harassed by Morris.

Morris, a former Asda worker, admitted murder and having an offensive weapon last week. He pleaded guilty to manslaughter at an earlier hearing, but prosecutors did not accept the plea. Pictured above, the scene of the murder

Sarah Whitehouse QC, prosecuting, said: 'She said that he had been sending abusive text messages to her and calling her repeatedly.'

A few days later, on April 19, she was granted a non-molestation order against Morris at the Central Family Court, which expired a year later.

Miss Day said in a statement he was controlling, verbally abusive and liable to lose his temper when he had been drinking.

About a week later, Miss Day successfully applied for a 'prohibited steps' order, which stopped Morris from removing their daughter from her mother or school.

In July, she began a new relationship with another man, but it did not seem to have caused any 'significant ill-feeling' between them.

But the problems between them 'escalated' from November 2016 when she made an application to the Child Maintenance Service for financial support from him.

Morris phoned the CMS about the application on November 2.

Ms Whitehouse said: 'He said that he had loans outstanding and was living on nothing.

'He complained that he was 'getting screwed' and that 'you literally are going to make me homeless'.

'He ended by saying, 'I'd rather not deal with this life than deal with what you lot are planning to do, yeah?'

They wrote to him the next day, telling him his contribution to his daughter's maintenance would be £1,898 a year - about £40 a week - which caused him to react badly.

Miss Day told the CMS that, when he heard about her application, 'he basically threatened my life and turned up at my workplace and said that if I don't cancel it then he's gonna kill me'.

On December 16 last year, he sent his brother Simon a Whatsapp message saying: 'And yes I did threaten to kill her if she didn't drop the cms claim. But at least I own up to my shit.'

However the claim was halted by Miss Day, and messages between November and early 2017 suggested he was providing money occasionally to her.

But in early 2017, Miss Day told Morris she was going to re-open the claim again.

Morris messaged her on January 3 saying: 'I'll go prison before they get a penny from me. You just love making a bad situation worse.

'Oh well, suit yourself. No one to blame but you from now.'

Ms Whitehouse said: 'Miss Day called her sister to report that the defendant had threatened to kill her, stating that her child would have no mother.'

She didn't make the claim, telling the CMS in May that Morris 'turned up at my workplace and followed me home threatening me that if I went through with the application he'd do something to me.